apply_filters( 'post_playlist', string $output, array $attr, int $instance )

3055	 * @since 4.2.0 The `$instance` parameter was added.3056	 *3057	 * @param string $output   Playlist output. Default empty.3058	 * @param array  $attr     An array of shortcode attributes.3059	 * @param int    $instance Unique numeric ID of this playlist shortcode instance.3060	 */3061	$output = apply_filters( 'post_playlist', '', $attr, $instance );3062 3063	if ( ! empty( $output ) ) {3064		return $output;3065	}3066 3067	$atts = shortcode_atts(